1. Field of the Invention
The present invention is related to a solar generator and solar cell thereof, and more particularly to a solar generator and solar cell thereof distributively performing maximum power point tracking (MPPT).
2. Description of the Related Art
Currently, solar energy can be harnessed by directly storing heat in a solid, liquid or gas or using photovoltaics to convert to electric energy and store the electric energy in solar cells.
With reference to FIG. 3, conventional solar cells include single crystalline silicon solar cells, polycrystalline silicon solar cells, amorphous silicon thin-film solar cells, CIS/CIS solar cells, CdTe solar cells, GaAs solar cells and the like and usually comprise a substrate (70), and a lower electrode (71), an optoelectronic semiconductor layer (72), an anti-reflection film (73) and an upper electrode (74) sequentially formed on the substrate (70). Given the single crystalline silicon cell as an example, The optoelectronic semiconductor layer (72) has a P-type semiconductor layer (721) and an N-type semiconductor layer (722), and a P-N junction therebetween. When light casts onto the P-N junction, electron-hole pairs are generated in the optoelectronic layer (72) due to a photovoltaic effect. Due to diffusion and an electric field in the optoelectronic layer (72), the electrons of the electron-hole pairs move toward the N-type semiconductor layer (722), and holes are moved toward the P-type semiconductor layer (721). Therefore, DC power is outputted from the upper and lower electrodes (74, 71) electrically and respectively connected with the N-type semiconductor layer (722) and the P-type semiconductor layer (721). As each solar cell only outputs low voltage DC power, multiple solar cells are combined to form a solar cell module, and then multiple solar cell modules can be arranged to form a solar cell sub-array and multiple solar cell sub-arrays may be further arranged to form a solar cell array to provide DC power of a desired voltage. All solar cells in the solar cell module are electrically connected to each other through wiring. An inverter is adopted to convert the DC power outputted by the solar cell array into AC power for performing MPPT.
However, shadow, shelter, incident angle of sunlight or faulty solar cells all affect power generation efficiency of the solar cells in a solar cell array. Hence, when MPPT is performed associated with the power generated by all solar cells, a maximum power of each solar cell fails to be effectively acquired, thereby causing a lowered maximum output power of the entire system.